1. Field of the Invention
The present invention relates to memory devices and more particularly, to a method for controlling a disk-type storage device.
2. Description of the Related Art
An optical disk drive is a typical disk-type storage device that uses an optical disc as the storage medium. The optical disk is rotated at given revolution speed (i.e., a given number of revolutions per minute) while an optical-pick-up reads from or writes to the optical disk in response to commands from a data processing unit. The optical disk revolution speed is about 200 rpm for a 4.times. (i.e., 4 speed) system and about 4000 for an 8.times. (i.e., 8 speed) system.
Generally, after completing a current process (e.g., reading, writing), the disk drive operating mode transitions from a process mode to an idle mode, thereby standing ready to respond to the next process command while maintaining the specified normal rotation speed. When the duration of the idle mode exceeds a specified reference time period without receiving a further process command, the disk drive automatically transitions to a standby mode. In the standby mode, disk rotation is stopped until a new process command is received. Thus, in order to transition from the standby mode to the process mode, the motor that rotates the disk must be restarted. Additionally, a sleep mode may be initiated by a sleep command from the data processing unit. When the disk drive is in sleep mode, process commands from the data processing unit are ineffective. The sleep mode may be released, but only after the disk drive is restarted or reset.
The purpose of controlling the disk storage device by application of the idle, standby, and sleep modes is to prevent unnecessary power consumption and heat generation, and to promptly respond to process commands from the data processing unit. However, the conventional method of selecting between the idle mode, that rotates the disk drive motor at normal speed, and the standby mode, that requires the restarting of the disk drive motor when a process command is issued, is inadequate in preventing unnecessary power consumption and heat generation.